But when he got busted in his apartment in a Lower East Side housing project in 2011, Monsegur — known online as “Sabu” — began secretly cooperating with an investigation that led to a wave of arrests across the US, Great Britain and Ireland.

Today, Anonymous still goes by the motto it unveiled in 2009: “We are Anonymous. We are Legion. We do not forgive. We do not forget. Expect us.”

But Monsegur, 35, says society has little to fear from the online anarchists in Guy Fawkes masks.

“Anonymous is irrelevant,” Monsegur told The Post.

“All it is now is a figment of hipsters’ imagination.”

“Mr. Robot” creator Sam Esmail has cited Anonymous — and especially LulzSec — as source material for his Emmy award-winning TV show and its anarchistic hacking network known as “F-society.”

Sam EsmailWireImage

“When they were eventually arrested by the FBI, it brought this entirely different criminal dimension to hacking. All of a sudden, it felt like the stakes across the world were raised,” Esmail told Vice’s Motherboard website in 2015.

Monsegur, who taught himself how to hack, said he hasn’t “watched too much of the show,” but noted: “Obviously the people from behind the show have borrowed ideas from Anonymous and from my story.”

“It looks plausible. The characters in the show are actually using tools and software that hackers use in real life,” he added.

“Mr. Robot” tells the story of split-personality hacker Elliot Alderson, played by Rami Malek, and his role in the upending of society by an anarchist collective called “fsociety,” whose followers wear masks that resemble “Rich Uncle Pennybags” from the Monopoly board game.

The USA Network show wrapped up its third season in December and has been renewed for a fourth.

Monsegur pleaded guilty to seven felonies as part of his deal with prosecutors and spent nearly eight months in Lower Manhattan’s infamous Metropolitan Correctional Center before being sentenced to time served in 2014.

During that time, Monsegur nearly mirrored some of the Elliot Alderson plot lines — he played chess with murderous drug kingpin and hip-hop mogul James “Jimmy Henchman” Rosemond, joked around with a bank robber dubbed the “White Glove Bandit” and met “a bunch of Colombian and Mexican cartel members whose names I prefer not to mention.”

Rami Malek as Elliot AldersonPeter Kramer/USA Network

The following year, Monsegur, who now lives in Queens, landed a job working remotely as a “white-hat hacker” for Seattle-based Rhino Security Labs, helping companies identify vulnerabilities in their computer systems.

He admits that “in comparison to what I used to do before, it’s not the same kind of thrill.”

“I’ve been doing this for so long, 20 years now, I’m just excited that I’m able to produce for the client. I’m glad I have the skill set to help these people, these corporations,” he said.